I had an awful experience at Burger King Lynwood Lane as the staff were extremely rude, not greeting me at all, and talking very “kortaf”

I had an awful experience at Burger King Lynwood Lane as the staff were extremely rude, not greeting me at all, and talking very “kortaf”. They also didn’t have milkshakes or mayonnaise and when I asked what was going on, the lady at the pickup window just responded snidely by saying “I don’t know.” while stuffing my order into my hands.